Direct developed azo dyes and their production



' Patented May-7, 1935 I i THEIR PRODUCTION Ernest F. Grether and Gerald H. Coleman, Mid- I .land, Mich., assignors to The DowChemical Company, Michigan Midland, Mich., a corporation of No Drawing. Application October 19,1929,

Serial No. 401,012 v iClaims. (crest-95 "The present invention is concernedwith azo dyes of the direct-developed type which may be produced by coupling diazotized amino-nitro diphenylamines into azo dye components, particdroxynaphthoic acid.

' water-insoluble azo dyes are formed.

' ularly into hydroxynaphthalene compounds, and i more particularly by coupling 4-amino-2.4'-dinitro-diphenylamines into imidazoles of 2.3-hy- It is known that azo dyes which are last to light and washing are produced by coupling'diazotized aromatic amines into-Naphthol AS, the

latter being 2.3-hydroxynaphthoic acid anilide, or intorelated compounds. We havefound that diazotized 4-amino-2'.4'-dinitro-diphenylamine andits substituted derivatives may be coupled into, imidazoles of hydroxy aromatic acids, or.,their substitution products, whereby new and Ourv invention, then, consists of the steps and new products hereinafter fully described and particularly pointed out in the claims, the following description setting forth but-several of the various ways in which the principle of our invention maybe used.

The herein described new azo dyesl'dye cotton,

and other fibers directly in fast and clear shades. They may be prepared by coupling the aforesaid diazo components into the above mentioned hydroxy-compounds inany of the ordinary Ways,

6. 'g. dyes may be applied by developing on the fiber, by printing a diazosolution upon padded goods accordingto the usual method, by using the nitrosamine salts of the corresponding bases, or

, may be prepared insubstance for use as pigments.

Mordanting or'other' auxiliary treatment for. promating the absorption of the dye by the fiber, or

after-treatment with metal salts such as'chromium, copper, or aluminum salts, for fixing the dye or modifying its color tone may be optionally employed in conjunction with the dyeing operation without departing from the spirit oi our in vention which is intended to include not'only the dyes themselves but also material dyed there- A preferred manner in which our invention may be carried out is illustrated in the following specific example. Q V

- Example Cotton fiber was impregnated'with an aqueous 'formula being:- 7

useful alkaline solution of 2'- (21,3 hydroxynaphthy1)- 4,5 para-tolylene imidazole5 The impregnated;

fiber wasthen rinsed water andirhmersed in a dilute aqueous sodium carbo'nate solution to which had been adde'da diazo solution of i4-amino-' 2,4-dinitro-diphenyl-amine. I The dye was raspberry v in. color,

sociation of the United States, Inc. is used to'des-- 'ignate the color, oi the above mentioneddye.

While in the examples; cotton fibershave been edition), issued, by The Textile Color Card ;As- V referred to as the materialto be dyed with the herein described new azo dyes, other naturalfor synthetic fibers may likewise be dyed therewith,'

such as, wool, silk, rayon and the like.

. Furthermore, we do not limit'the invention; to

the use of the; specifically aforementioned inter-.

.mediates. As diazo components may beusedthe diazo compounds prepared from substituted; de- ,35?

rivatives of the aboveutilized diazo component} Other modes plained, "change being made as regards the, steps or material employedprovided the stepsiorfin 'gredientsstated byany-of the following claims or the equivalent of such be employed. 1

We therefore particularly jpoint outand dis- .tinctly claim as our invention:

such as the halogen, nitro, alkyl, ether, or other derivatives; 1 y

of applying the principle of our invention may be employed instead of theone-ex- 40 I l Y 1. The method of making an azo dye which" comprises coupling diazotized 4-amino-2',i-di I nitro-diphenyla'mine with an imidazole of 2,3-hydroxynaphthoic acid.

2. As a new product, an azo dye having the general formula;

wherein R" represents a residue of the benzene 15 series.

3. As a new product, an azo dye having the formula;

4. Fiber dyed with a dye as claimed in claim 2.

5. Fiber dyed with a dye as claimed in claim 3.

ERNEST F. GRETHER. GERALD H. COLEMAN. 15 

